Autism Spectrum Disorder: Sleep Characteristics in Children and Adolescents, and Their Relationship with Probable Sleep Bruxism, Anxiety, and Cortisol and Melatonin Levels-A Cross-Sectional Study of Children in Brazil.

The study described the sleep characteristics (SC) of children/adolescents with Autism Spectrum Disorder (ASD), and examined their association with medication use, support level, chronotype, probable sleep bruxism (PSB), anxiety, salivary levels of cortisol (SalC) and melatonin (SalM). Methods: Following anamnesis and dental examination, anxiety was assessed using the SCARED questionnaire. The SCs were determined by two age-appropriate questionnaires, and the percentage of negative SCs (%Neg) was recorded. Saliva samples were collected to measure SalC and SalM levels. The sample comprised 85 ASD patients aged 2-16 years, of whom 80%, 50.6% were classified as support level 2, 83.5% used medication, 84.7% had an afternoon chronotype, 72.9% presented PSB, and 48.2%, anxiety. The mean %Neg was significantly higher in patients using medication (49.29 ± 15.88; p = 0.03) and those requiring more support (level 1: 41.57 ± 14.45; level 2: 50.78 ± 15.54; level 3: 55.11 ± 23.44; p = 0.019). Patients with anxiety showed a higher %Neg (51.31 ± 16.33) than those without anxiety (43.65 ± 15.79). The mean SalC and SalM levels were 13.29 ± 13.39 and 299.91 ± 241.77, respectively.. In children aged 2-6 years, one rhythmicity SC and two separation-related SCs were associated with SalC (p < 0.05); lower SalM levels were found in patients who "slept alone" (p = 0.02). In older patients, "moving while sleeping" was associated with lower SalC (p = 0.05), and three additional SCs were linked to reduced SalM levels (p < 0.05). The presence of negative SCs in ASD patients was more common in those taking medication, requiring more support, and presenting anxiety. Furthermore, SalC and SalM levels were associated with specific SCs, especially among individuals aged (7-16).